Hydraulic apparatus



ugl, 1950 J. K. WILLIAMS 2,517,518

HYDRAULIC APPARATUS Filed May 29, 1945 2 Sheets-Sheet 1 1115515141lfinllllflnnnlnnf.

atented ug. 1, 195.0

UNITED STATES PATENT OFFICE HYDRAULIC APPARATUS John K. Williams, Bellmead, Tex., assigner to Consolidated Vultee Aircraft ACorporation, San

Diego, Calif., a corporation `of Delaware Application May 29, 1945, Serial No.596,550

(Cl. 18S- 2.5)

2 Claims.

The invention relates to hydraulic systems provided with means for removing air from the uid.

In hydraulic systems, such as those used in aircraft, it is desirable and advantageous to provide a reservoir for the hydraulic iiuid from which iiuid `is drawn and forced under pressure to the actuating device and to which it is returned from the actuating device with means for de-aerating or `eliminating air from the iluid to prevent cavitation in the hydraulic system. In aicraft weight, simplicity and compactness in construction, and adaptability of being easily serviced are desiderata.

One object of the invention is to provide apparatus including a reservoir for the hydraulic fluid and de-aerating means, and which is light in Weight, simple and compact in construction.

Another object of the invention is to provide apparatus for this purpose in which the `(le-aerating means includes a lter which is contained in a separate receptacle in the upper portion of the reservoir and a depending tube for delivering illtered fluid into the lower portion `of the reservoir, in such manner that the iiuid will be de-aerated before it is drawn into the hydraulic system.

Another object of the invention is to provide improved means for by-p'assing return fluid around the filter in the event that the return fluid exceeds the capacity of the filter.

Another object of the invention is to provide apparatus of this character which may be constructed, mainly of sheet or plate metal, for lightness in Weight.

Another object of the invention is to provide apparatus of this character in which the parts are readily removable for servicing, replacement and repair.

Other objects of the invention will appear from the detailed description.

The invention consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a vertical section of apparatus embodying the invention.

Fig. 2 is a horizontal section taken on line 2-2 of Fig. 1.

Fig. 3 is a horizontal section taken on line 3 3 of Fig. 1.

The invention is exemplified in apparatus which comprises a tank Yor reservoir, generally designated l0, which is constructed so that it may be formed of suitable sheet or plate metal for lightness in weight. Reservoir Il) comprises a cylindreal body-portion which is formedof semi-cir-I cular plates l2 provided with flanges I3 and welded together to form a completely cylindrical bodyportion; aconcavo-convex bottom I6 lapping the lower ends of plates I2 `and welded thereto as at Il; and an upwardly and inwardly curved annular top-member I8 which is welded to the bodyportion of the reservoir asat I 9 and provided with an inturned horizontal top-flange 20. The reser- Voir is adapted to retain a columnof oil or of hydraulic fluid which is drawn therefrom, usually by a pump, through an outlet-nipple 22 which is welded as at 23 to the concave-convex bottom i6 and has its axis extending tangentially to the axis of reservoir l0. Preferably, these parts of the reservoir are formed of plate-metal, for lightness in weight. The flanges i3 which project from the cylindrical body-portion l2 of the reservoir Ill are provided with holes for screws whereby the reservoir may be conveniently installed on a permanent support. A tting V(i5 for "a drain '6B is welded in the central portion of bottom f6.

A receptacle, generally designated 30, extends into the vupper portion of the receptacle into which the iluid returned from the system is discharged, for passage through a lter Vfrom which itis conducted into the column of iluid in the lower portion of the reservoir. Receptacle 30 comprises a cylindrical wall 3l, a concavo-convex or approximately hemispherical bottom 32, and an upwardly and initially sloping upper portion with an integral out-turned ange 33 on the upper end which laps the top-flange 20 on the reservoir. This construction of the receptacle 30 makes it possible to form it of sheet or plate metal and light in weight. The receptacle forms a removable `closure for the top of the reservoir. The cylindrical side wall 3l of receptacle 30 is spaced Afrom the surrounding wall of the reservoir so that the annular space between may be utilized for the air separated from the hydraulic uid in the lower portion of the reservoir. This provides for compactness in construction and li-ghtness in weight.

` A concavo-c'onvex cover-plate 25 is provided for the upper end of, and forms a detachable closure for themtop of, the receptacle. The rim of 'cover-plate 25 extends over the annular flange 33 on receptacle 30, a packing-ring or elastic gasket 28 is interposed between flange 33 `on receptacle 30 and top ange 20 on the reservoir. A packingring or elasticgasket 29 is also interposed between ilange 33`on receptacle 3U and the rim of cover-plate 25. Preferably, these packing-rings are circularin cross-section and conI afname tacle 30 and the receptacle may be removed from the reservoir for access to the latter. l

A suitable tting 39 is welded in an outturned ange formed on cover-plate and connected to a pipe 49 for the huid returned from the hy draulically actuated device. A similar fitting 43 may be similarly welded inuthe cover-plate 251 for by-passing excess fluid from the pump which 4 ceptacle to a tube 6D which depends from the center of said bottom, and extends into the column of uid maintained in the lower portion of reservoir I0. Tube 5@ is provided at its lower end with a curved terminal 6I which extends radially outward and upwardly. The fluid is directed away from the discharge connection 22 through `which fluid is `drawn from the reservoir. .Tube 60,

. for lightness in weight and stiiness', is preferably 63 which are Welded together.

formed of plates B2 which are semi-circular in cross-section and provided with abutting anges The bubbles formed in the hydraulic uid as a result of the fluid flowing through lter 41, expand by reason of the reduced pressure of the fluid in the reservoir and will pass upwardly to the top of the fluid I columrrwhich may be at the level indicated at a, v where they are released into the space above the draws fluid from the reservoir and forces it"'to" the hydraulically actuated device, into receptacle 36.- AA ller-plug 4I is screwed into a fitting 42 which is welded in the cover-plate 25.

A plate 45 extends across and is liXed and welded as at 44 inthe lower portion 32 of receptacle 30 and divides the space within the receptacle 30 into upper and lower chambers. The central portiony 52 of plate'45 is upwardly convergent and provided with openings 53 through which the hydraulic fluid from the filter flows into the lower chamber between plate 45 and the concavo-convlex bottom of receptacle 30.

An annular flter-element 41 is disposed in the upper chamber in receptacle 3B for the hydraulic fluid returned to said chamber and through which the fluidV passes to the central space within the filter which communicates with the openings 53 in central-portion 52 of plate 45 so that the fluid which has passed through the filter will flow into the lower chamber in receptacle 39. The lter element 41 may'be of any suitable construction to form larger bubbles in the fluid passing through the lter so that when the uid is discharged into the column of fluid in thev lower portion of the reservoir, the bubbles will be released and separated from the fluid. The filter-element 41 has an annular end which is seated on an elastic gasket 45 which is conned in an annular groove in plate 45. A top plate 49 extends over the upper end of the filter-element 41 and an elastic gasket 48 is confined in an annular groove in said plate and engages the upper end of the filter-element 41. Plate 49 forms aclosure for the upper end of the filter-element 41 so that the fluid will pass from the chamber in receptacle 30 around said elementl through the filter to the central chamber therein from which it will flow through the openings 53 in -plate 45 into the lower chamber of receptacle 33. Adome-like plate 51 overlies the top-plate 49.' A boltv56 extends through dome-plate 51, plate 49, and is screwfthreaded to a collar 58 which is welded'to the central portion of ythe bottom faceof plate 49 and is adapted to clamp the filter-element 41 between plates 45 and 49. Upon withdrawal of bolt 58 from plate 45, dome 51, plate 49 and filter-element 41. may be removed from receptacle 3l) for servicing,v replacement or repair. This construction provides means foireadily removing from, and reassembling these partsin,`the recep- Vins liquidcolumn in the reservoir. The fluid returned from the actuating device to thev receptacle 30 is usually under pressure so that there will'beY a drop of pressure in the reservoir. By providing a tube 50 depending from receptacle 39 and discharging the fluid radially outward and upwardly in the concavo-convex lower portion of the receptacle and away from the outlet connection 22, the separation of the air from the liquid is accelerated.

A vent-pipe 68 is provided in the upper portion of zthe reservoir for the escape of air separated lfrom the hydraulic fluid. This pipe, for lightness of weight, is formed of tubular, horizontal and vertical sections which are welded together with a flange G9 on the horizontal section which is welded `to a fitting 69 which is welded in a. flange .on one of the semi-cylindrical portions l2 of the reservoir I0. This vent-pipe 88 permits escape of air from and reduces the pressure of the fluid in the reservoir. Dome-plate 51 is provided with openings 14 through which huid can pass from the upper portion of receptacle 30 into the space between said dome-plate and plate 49. A pair of relief valves are provided for by-passing iiuid from the upper portion of the receptacle 30 into the space within the filter-element 41, in the event that the surge of iiuid returned from the actuated device exceeds the capacity ofthe filter. Each of these: comprises a cylindrical casing 15 welded in and depending from plate 49, an upwardly closing valve-member 16, and a spring 11 urging valve-member 16 to its closed position and loading it so it will remain closed until the surge of fluid becomes excessive.

A sight-glass 12 is communicatively connected to the reservoir for observing the heighth of the column of huid therein.

The operation of the apparatus will be as follows: return fluid from the hydraulically actuated device will be delivered under pressure into the upper end of the receptacle 35 from which it will now throughI the filter-element 41 which will cause the" vesicles of air to form bubbles in the fluid. From the chamber inside the filter-element 41, the huid will flow onto plate and through openings 53 into the chamber in the lower portion of receptacle 30 :and thence downwardly through tube S0 `and be discharged into the co1- umn of fluid in reservior l0. The curved terminal 6I directs the fluid radially outward. from the centter of the' reservoir and' away from the outlet connection. 22' and also upwardly. The bubbles in the fluid discharged from tube iiow upwardly through the column of. fluid, and Vexpand by reason of the reduced pressure inl the reservoir. When the bubbles reach the surface of the co1'- asians ui'nn `of fluid they join the `air in the upper portion of the reservoir and are carried olf through vent-pipe 68. 'Ihe uid drawn through nipple 22 is taken from a portion of the column of iiuid which is remote from the bubbles discharged from the tube 50. In the event that the surge of the fluid delivered into the upper portion of 3E in receptacle 30 exceeds the capacity of the lterelement 41, the fluid will open one or both of the valve-members 16 and by-pass the excess into the chamber inside the lter-element 41 so it will flow through openings 'Hl in dome-plate 51 in plate 45 and tube 60 into the column of fluid in reservoir ,The construction described is adapted to be fabricated of metal sheets or plates so that it will be relatively light in weight for advantageous use in aircraft. The receptacle 30 containing the filter to which the discharge pipe is connected may be readily removed from the reservoir upon removal of cover-plate 25. The lter-element 4l may be readily removed from the receptacle for servicing upon removal of bolt 56 which clamps it between plates 49 and 45. The depending tube B for conducting the filtered fluid into the lower portion of the column of fluid in the reservoir with its lower terminal adapted to direct the fluid away from the outlet duct and upwardly through the column of fluid accelerates the release of the entrained air to the upper portion vof the reservoir and the vent-pipe 68. Flanges I3 on plates l2 forming the cylindrical portion of the reservoir provide simple means for supporting the reservoir in airplanes. The tube `69 delivers fluid from the lter into the column in the reservoir without substantial decrease in the capacity of the reservoir and the embodiment of the receptacle for the lter within the upper portion of the reservoir contribute to compactness in the apparatus. The apparatus can be fabricated mainly of sheet or plate metal for saving of weight. The relief valves provide for by-passing the fluid delivered into the lter receptacle to the reservoir when the fluid is in excess of capacity of the lter.

The invention is not to be understood as limited to the details described, since these may be modified within the scope of the appended claims without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

1. `Combined apparatus for filtering and deaerating hydraulic fluid for actuating a hydraulically operable device, comprising: a cylindrical tank for retaining a column of iluid, having a top opening and a cancavo-convex bottom; a receptacle separably supported on and forming a closure for the top opening of the tank and having a cylindrical wall of lesser diameter than and depending into the tank to provide an annular air space in the upper portion of the tank around the receptacle; a cover separable from and forming a closure for the top opening of the receptacle: a nlter completely contained 1n the receptacle and removable therewith from the tank; an inlet connection in the cover for delivering fluid to the lter in the receptacle; a pipe removable with and depending from the bottom of, the receptacle and having a curved lower end for tangentially delivering iiuid from the bottom of the receptacle over the concave bottom of the tank, an outlet connection for the filtered fluid from the lower portion of the tank; and :a vent for air in the annular space between the upper portion of the tank and the receptacle.

2. Combined apparatus for ltering and deaerating hydraulic iluid used for actuating a hydraulically operable device, comprising: a cylindrical tank for retaining a column of fluid having an upwardly and inwardly sloping upper end portion provided with an integral, inturned ange and a top opening; a receptacle forming a closure for the top opening of the tank having a cylindrical wall of lesser diameter than and depending into the tank to provide an annular air space in the upper portion of the tank around the receptacle and provided with a top flange separably supported on the inturned flange of the tank, and having a concave-convex bottom; a cover having its rim extending over and separably supported on the outturned liange on the receptacle, means demountably securing together the cover, the flange on the receptacle, and the ange on the tank; a lter completely contained in the receptacle and removable therewith from the tank; an inlet connection in the cover for delivering fluid to the lter in the receptacle; a pipe removable with and depending from the bottom of the receptacle and having a lower, curved end for tangentially delivering fluid from the concave bottom of the receptacle over the concave bottom of the tank; an -outlet connection for the filtered fluid from the lower portion of the tank; and a vent for air in the upper portion of the annular space between the tank and the receptacle.

JOHN K. WILLIAMS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,000,405 Healy Aug. 15, 1911 1,054,702 Maranville Mar. 4, 1913 1,109,103 Baum Sept. 1, 1914 1,463,990 Wilson Aug. 7, 1923 1,471,705 Porter Olct. 23, 1923 1,514,118 Wright Nov. 4, 1924 1,840,079 Bradley Jan. 5, 1932 2,043,379 Justus June 9, 1936 2,057,932 Bolser Oct. 20, 1936 2,132,770 Weidenbacker Oct. 11, 1938 2,165,703 Holmes July 14, 1939 2,297,297 Walker Sept. 29, 1942 2,376,794 McCulloch May 22, 1945 

